Initial Experience With Subchondral Stabilization for Grade II Stress Fractures of the Midfoot and Forefoot

Stress fractures of the foot are often preceded by magnetic resonance imaging evidence of bone marrow edema. While new evidence suggests intraosseous injection of calcium phosphate ("subchondral stabilization") can alleviate symptoms associated with bone marrow edema, no data yet exist regarding its use in developing mid- and forefoot stress fractures. Fifty-four patients who underwent subchondral stabilization of various midfoot/forefoot bones in our practice were observed over a 5-year period. All patients were unresponsive to standard nonoperative measures for at least 6 weeks, and all had clinical exams and advanced imaging consistent with a Kaeding-Miller Grade II stress fracture. Forty patients were included with a mean age of 54.3 ± 14.9 years and mean follow-up of 14.1 ± 6.9 months. Patients saw a significant decrease in visual analog scale (VAS) pain as early as 1 month postoperatively (p < .05). Mean postoperative VAS at 12 months was 2.11 ± 2.50, and mean reduction in VAS pain from preoperative to 12 months postoperative was -5.00 (95% CI -3.44 to -6.56, p < .05). Fourteen patients (34%, 14/41) were entirely pain free at 12 months. Higher preoperative VAS pain scores (unadjusted odds ratio [OR] 2.13 [95% CI 1.20-3.77], p = .010) and treatment of more than 1 bone (unadjusted OR 6.23 [95% CI 1.39-27.8], p = .017) were associated with a greater likelihood of not achieving a pain free status at 12 months. Our initial experience with subchondral stabilization suggests the procedure may be safe and effective for use in many Kaeding-Miller Grade II stress fractures of the mid- and forefoot.